基于代谢途径的高效微生态菌系降解二氯苯的机理及过程调控

Benzene series are widely used in industrial process, important precursors of ozone pollution and aerosol formation. Because of bioaccumulation, toxicity and carcinogenicity, they were identified as priority pollutants in the voltaic organic compounds (VOCs) control strategy. In our project, dichlorobenzene was selected as the target pollutants, and the biodegradation pathways and intermediates were analyzed by technology of GC-MS, HPLC, IC and so on. Based on the co-metabolism theory, the domestication mode of “intermediates+target pollutants” was constructed, and the specific bacteria were inoculated to the microbial flora through orient domestication in order to construct robust microbial system. The variation of microbial community structure was analyzed by the 16S rRNA, high-throughput sequencing and FISH, and the mechanisms of microbial community structure diversity response to the biological purification of dichlorobenzene were further elucidated in genome level. Micro ecological control mode was conceived by utilizing toluene and methyl alcohol as the co-substrate, and the variation of metabolic enzyme activity, microbial community structure, biofilm characters, and EPS was measured to analyze the promotion mechanism of ion electrode on enhancing biodegradation. The process of dichlorobenzene mass transfer in biofilm was analyzed by the technical means of dissolved oxygen microelectrode, ion electrode and the VOCs normalized kinetic model “three-phase absorption / two-phase adsorption” was established in order to explain and characterize the degradation kinetics of biological treatment of waste gas. Besides, the establishment of normalized kinetic model could support and guide the industrial waste gas treatment process and reactor design.

苯系物是形成气溶胶和臭氧污染的重要前驱体，已成为VOCs控制的首要污染物。以二氯苯为目标污染物，采用GC-MS、HPLC、IC等揭示其生物降解路径和中间产物；基于协同代谢理论设计“中间产物-目标污染物”的定向驯化模式，将专性菌引入定向驯化的菌群，构建高效稳定的微生态菌系；应用16S rRNA 技术、高通量测序和FISH等分析菌落结构的变化，从基因组水平上阐明微生物群落结构多样性对净化VOCs的响应机制；分析以甲苯、甲醇作为共代谢物对二氯苯的净化作用机制，以代谢酶活性、菌系结构、生物膜特性和EPS的响应解析金属离子强化生物净化二氯苯的促进机制，以此建立微生态调控。以溶解氧微电极、离子电极等技术手段解析生物膜净化二氯苯的传质过程，建立基于传质-反应过程和机理的生物净化二氯苯的“三相吸收/两相吸附”归一化动力学模型，解析VOCs生物降解动力学行为，为VOCs废气处理提供理论与技术支持。

难溶、难降解的苯系物是形成气溶胶和臭氧污染的重要前驱体，已成为VOCs控制的首要污染物。本项目以二氯苯等为目标污染物，基于共代谢理论具有高活性、持久性和兼容性的微生态菌系；以表面活性剂和金属离子强化生物净化效果，以共代谢机制调控降解体系，实现对难降解VOCs的矿化；建立基于传质-反应过程和机理的动力学模型。.（1）建立以污染场地为菌源的“甲苯-邻苯二酚-目标基质”共代谢协同驯化模式，获得苯系物、氯苯等降解菌系，对温度（25-35℃）、pH（5-8）及盐度（0-3g/L NaCl）具有很好的适应性。.（2）探索共代谢强化调控降解机制：混合菲、芘浓度小于50mg/L时，碳源间与微生物间的交叉适应和共代谢等作用机制；苯、甲苯和乙苯初始浓度为50- 100mg/L时，对净化体系正向促进作用明显。.（3）蜡质芽胞杆菌Bacillus cereus DL-1净化1,2-二氯苯、土壤短芽孢杆菌BrevibacillusagriDH-1净化1,3-二氯苯的降解途径是“先部分或全部脱氯后开环”不同于通常的“先开环再脱氯”。降解值为0.47 gCl- / g1,2-二氯苯，接近理论值的0.48，矿化率为41.67％，表明DL-1对1,2-二氯苯具有高效降解能力及矿化能力。.（4）研究鼠李糖脂（RL）与Fe3+、Mg2+等强化BTF工艺作用：RL为120mg/L时BTF对1，2-二氯苯降解率最高为79.23%，提高24%；RL耦合Mg2+可使启动期由通常数月缩短至20d，去除率提高11 %。Fe3+或Mg2+与含氧官能团作用形成EPS-金属离子-EPS三维结构，膜稳定性强。.（5）基于气-液相间传质与生物反应过程，构建BTF净化氯苯废气的气-液-生物膜三相稳态动力学模型，可准确预测去除负荷，反推工况(液体表面流速、空床停留时间、进气浓度)阈值，定量调控优化工艺性能。为难降解VOCs废气处理提供理论与技术支持。